A number of different filtering devices are known for separating solid matter from water, such as, for example, waste water in septic tanks. Many of the known devices for removing waste water from septic tanks allow the solid materials to settle to the bottom of the tank and allow bacteria to react and digest the solid materials. The by-products of the reaction of the solid or semi-solid matter with the bacteria then pass through filtration to remove the remaining small particles, with the waste water being removed by overflow or by discharge pumps in to a drain field. Known filtration systems employ a filter cartridge having a stack of settling plates with a weir wall integral to the top side of the settling plate. Such known filters, however, only have one level of filtration or screening. Therefore, any solids smaller than the aperture either pass onto the drainfield or become trapped on the settling plate requiring more frequent servicing. Other known systems employ a filter that has a stack of inclined filter plates that have an integral weir wall extending from the settling plate. This design allows solids to side to slide back down the inclined surface before passing through the aperture. However, in these known designs smaller particles that pass through the aperture become trapped inside by the weir wall and again require frequent servicing.